People from Bitcoinlandia tend to view other crypto-currency systems with in a myopic way. XRP are there only if you want them. They can be pretty useful to provide liquidity between U.S. dollar denominated IOUs from different gateways (and with the liquidity provider / arbitrageur making a small profit on the trade). Regular users won't see these behind the scenes activities, they will just enjoy the benefits of highly liquid markets and the network effects that Ripple allows.
Right. The title of this thread should really be Ripple
and Bitcoin. It's not altogether clear that XRP will catch on as a currency at all. I see Bitcoin and Ripple as very complementary, and people should focus on making them work together rather than dividing into separate camps. Ripple does nothing to prevent governments around the world from debasing their currencies (and does nothing to prevent OpenCoin from debasing XRP), so anyone concerned about this will hold Bitcoin. It can be the digital gold that backs up the Ripple network. At the same time, we all know how stressed at the seams Bitcoin has become serving as a micro-transaction system. Let Satoshi Dice and others move their small transactions over to Ripple and let Bitcoin be a store of value.